• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.779-786
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• 2009

This paper deals with $H_{\infty}$ fuzzy control problem of discrete-time nonlinear Markovian jump systems with time delay. The Takgi and Sugeno fuzzy model is employed to represent a delayed nonlinear system that possesses Markovian jump parameters. A stochastic mode dependent Lyapunov function is employed to analyze the stability and $H_{\infty}$ disturbance attenuation performance of the Markovian jump fuzzy system with time delay. Stochastic Lyapunov function is dependent on the operation modes of the system. A sufficient condition for the existence of fuzzy $H_{\infty}$ controller are given in terms of matrix inequalities. Also numerical example is presented to illustrate the efficient of the proposed design methods.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.619-622
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• 2001

실시간 응용 프로그램은 미디어 데이터간에 만족되어야 할 동기화 제약조건(synchronization constraints)을 가지고 있다. 이러한 제약조건은 프리젠테이션 되어야 할 미디어 데이터간의 지연시간 및 서비스 품질을 나타낸다. 미디어 데이터간의 지연시간 및 서비스 품질을 효율적으로 표현하기 위해서는 이에 적합한 새로운 동기화 기법이 요구된다. 제안된 논문은 가변적 전송 지연 시간을 흡수하면서 미디어 데이터간의 동기화를 수행하는 동적 동기화이다. 즉, 최대 지연 지터 시간을 이용한 동기화 구간 조정과 지연시간의 변화에 따른 가변적 대기 시간을 융통성 있게 처리하여 미디어 데이터간의 동기화 요구를 만족시킬 수 있는 기법이다. 본 논문은 동기화 구간 조정을 처리하기 위해 지연 지터를 적용함으로써 트래픽 증가로 인한 미디어 데이터의 손실 시간 및 지연시간의 변화로 인한 데이터 손실을 감소시켰다. 그리고 스무딩 버퍼의 대기 시간을 가변으로 처리함으로써 지연시간의 변화로 인한 불연속을 감소시켰다. 제안된 논문은 고품질 서비스의 보장을 요구하는 시스템에 적합하며 재생율 증가와 손실율 감소 등 서비스 품질을 향상시켰다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1124-1133
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• 2000

Advanced Intelligent Network Intelligent Peripheral (AIN IP) is one of the AIN elements which consist of Service Control Point (SCP), Service Switching Point (SSP), and IP for AIN services, such as play announcement, digit collect, voice recognition/synthesis, voice prompt and receipt. This paper, featuring ISUP/INAP protocols, describes the procedures for call setup/release bearer channels between SSP/SCP and IP, todeliver specialized resources through the bearer channels, and it describes the structure and procedure for AIN services such as Automatic Collect Call (ACC), Universal Personal Telecommunication (UPT), and teleVOTing(VOT). In this environments, the delay characteristics of If system is investigated as the performance analysis, Policy establishment.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.334-336
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• 2002

본 논문에서는 스타그래프 다중처리시스템을 위한 새로운 프로세서 할당방범을 제안한다. 기존의 할당방법은 프로세서 단편화로 인해 작업을 처리할 서브스타를 형성하지 못하면 프로세서 할당이 지연되는 문제점이 있었다. 이러한 할당 지연은 작업의 대기시간을 증가시키고 시스템의 성능 향상을 제한한다. 본 논문에서 제안하는 할당방법은 프로세서 할당 지연이 발생하면 동적할당테이블을 사용하여 단편화된 프로세서의 주소론 재생성한다. 새로운 주소의 프로세서들로 가용 서브스타를 형성하여 할당함으로써 작업의 대기시간을 줄이고 프로세서 단편화를 최소화한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.11
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• pp.1206-1218
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• 1992

Token ring systems which control to switch the data stream of networks by passing the token have been widely used to medium access controls in many ring or bus topology LANs. The system could be modeled for analysis as single-server-multi-queue system of the cyclic service method. These concepts could be expanded to multi-token ring systems interconnected with single ring consisting of bridges implemented simply to be stored and transmitted. In the proposal for the performance analysis of the interconnected token ring system, in has been assumed M/G/1 queueing model that frame arrivals are the Poisson process at each station queue and frame sizes are independently and identically distributed. And the average time delays were analyzed mathematically for arbitrary frame transferred from source station to destination area. The time delay of the frame transmission could be explained as the sum of the average time which the token passed from arbitrary position to source station, such as the waiting time in the source station transferring the previous arrival frames, and the propagation time from source station to interdestinated point. These delays were given as the sum of the duration from inner and outer bridge queues, the time delays from inner and outer bridge queues, and the time from outer bridge queue to destination station. These results were investigated by varing parameters effected to total time delays. In the results, those factors to be effected to dominant the total time delays were increased were in the cases of the high arrival rates and the high ration of destination of the other outerring. The system were shown the time delays increased exponentially in spite of the priority service policy. In order to decreasing the number of outerrings and increasing the number of nodes in backbone relatively, so the systems could be decreased the total delay in the interconnected token ring system.

• Journal of Advanced Navigation Technology
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• v.18 no.5
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• pp.501-507
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• 2014

A dynamic system is called positive if any trajectory of the system starting from non-negative initial states remains forever non-negative for non-negative controls. In this paper, new sufficient conditions for asymptotic stability of the interval positive time-varying linear discrete-time systems with time-varying delay in states are considered. The considered time-varying delay time has an interval-like bound which has minimum and maximum delay time. The proposed conditions are established by using a solution bound of the Lyapunov equation and they are expressed by simple inequalities which do not require any complex numerical algorithms. An example is given to illustrate that the new conditions are simple and effective in checking stability for interval positive time-varying discrete systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1C
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• pp.54-60
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• 2005

In this Paper, an adaptive microphone array system with self-delay estimator is proposed. By showing that the adaptive blocking matrix (ABM) of the generalized sidelobe canceller (GSC) can estimate the relative time delay between each sensor, the proposed system utilizes the ABM not only for blocking target components in the blocked signal path, but also for estimating the relative time delay. Therefore, the proposed system requires only the GSC structure while maintaining the system performance similar to the conventional system using an additional time delay estimator as a preprocessor. Simulation results show that the performance of the proposed system is identical to the conventional system that uses an additional time delay estimation module.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.573-576
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• 2018

아파치 카프카(Apache Kafka)는 데이터 스트림을 실시간 전달하는 분산 메시지 큐잉 플랫폼이다. 카프카는 대다수의 실시간 처리 응용에 사용되는데, 흔히 데이터 스트림의 발생지와 실시간 처리 시스템 사이(입력) 또는 실시간 처리 시스템과 처리 결과의 목적지 사이(출력)에 배치된다. 분산 기술을 도입한 카프카는 다른 메시지 큐잉 기술에 비해 대용량 데이터 스트림을 더욱 빠르게 전달 할 수 있다는 장점을 갖는다. 하지만, 카프카에 적재되는 데이터 스트림의 양과 실시간 처리 응용의 수가 증가할수록 메시지 지연시간은 매우 높아질 수 밖에 없다. 본 논문은 이러한 카프카의 메시지 지연 문제를 해결하고자 카프카의 로드 쉐딩 엔진을 제안한다. 로드 쉐딩의 세 가지 필수적인 결정에 따라, 제안하는 로드 쉐딩 엔진은 카프카의 프로뷰서에서 지연시간이 기준치를 초과할 경우 일부 메시지 전송을 제한하여 지연시간을 줄인다. 실제 실시간 처리 응용으로 실험한 결과, 단일/다중 데이터 스트리 모두 로드 쉐딩이 바르게 작동하여 지연시간이 지속적으로 증가하지 않고 오르내림이 반복되는 추세를 보였다. 본 연구는 데이터 스트림의 입출력을 카프카로 관리하는 실시간 처리 응용에 로드 쉐딩 기법을 적용한 첫 번째 시도로서, 앞으로 데이터 스트림 처리에 사용될 의미 있는 연구라 사료된다.

• Journal of IKEEE
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• v.13 no.1
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• pp.36-40
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• 2009

In control of time delay systems, if the informations about the system model and the disturbance can be estimated exactly, the ideal response can be achieved by using Smith predictor controller. Therefore, in this paper, an adaptive algorithm is proposed to control time delay systems existing modelling errors and disturbance. An adaptive observer to estimate disturbance and system model is designed and adaptive laws adjusting the observer are proposed. The new Smith predictor controller is designed using the proposed adaptive observer. As a result, the proposed controller can eliminate the effects of the disturbance and the modelling error. The effectiveness and the improved performance of the proposed system are verified by computer simulation.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.239-243
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• 2013

This paper presents the output feedback control design for triangular nonlinear systems with input delay. The proposed controller is composed of a high gain observer and a linear controller. It is shown that by using Lyapunov-Krasovskii theorem, the proposed controller ensures an asymptotic stability for sufficiently small input delay. Finally, an illustrative example is given in order to show the effectiveness of our design method.